1. Field of the Invention
The present invention relates to a an implant adapted to be utilized in the treatment of a human eye having a deficiency of tears and more specifically relates to an implant capable of forming a differential image in an eye wherein the implant includes an elongated member including a central axis and having at one end thereof a distal section which, in the preferred embodiment, is in the form of a collapsible expanded section.
The distal section may terminate in a distal tip which extends in a direction substantially parallel to the central axis. The elongated member including the distal section and collapsible expanded section are dimensioned to be inserted into and passed through a punctum opening of an eye into the canaliculus. In its broadest concept, an energy wave blocking material responsive to an energy wave, which may either be in be form of sound waves vibrating at frequencies greater than 20,000 cycles per second, e.g., ultrasound waves, or electromagnetic radiation is incorporated into the implant, which upon everting of an eyelid of an eye and exposing the implant to an appropriate energy wave, forms a differential image pattern showing the location of the implant in the eye.
In the preferred embodiment, a substantially opaque material responsive to electromagnetic radiation in the wavelength of visible light is incorporated into the implant which, upon everting of an eyelid of an eye and exposing the implant to electromagnetic radiation in the wavelength of visible light, forms a differential image pattern visually showing the location of the implant in the eye.
This invention also relates to a method for treating external eye conditions due to a deficiency of tears utilizing the implant having at one end thereof a distal section, preferably in the form of a collapsible flared section, terminating in a distal tip which extends in a direction substantially parallel to the central axis.
2. Description of the Prior Art
It is known in the art that certain eye problems are related to the volume of tears on the surface of the eyes. Certain of these problems include dry eyes, corneal ulcer, conjunctivitis, blepharitis, contact lens problems and many other external eye diseases.
One method for treating for a deficiency of tears is disclosed in U.S. Pat. No. 4,660,546 which discloses a method for treating external human eye conditions due to a deficiency of tears which includes the step of temporarily blockading the canaliculus of the patient and observing over a preselected period of time the response of the patient's eye to the temporary blockage and to determine if any improvement in the eye condition has been achieved in response to the occlusion.
If an improvement in eye condition is noted, an implant is placed within the canaliculus of the eye of the patient. A temporary blockading of the canaliculus is performed by placing a dissolvable, removable element, which may be in the form of a collagen material or other dissolvable material such as, for example, catgut, in the canaliculus. Unless removed shortly after insertion, the dissolvable implant is typically absorbed by the body in approximately a two-week period.
A determination is first made if the canaliculus blockage results in an improvement in the eye condition or other conditions caused by related nasal congestion warranting permanent blockage of the canaliculus, for example, the patient will respond to a partial 60% to 80% retention of constant tears.
If permanent blockage of the canaliculus is warranted, U.S. Pat. No. 4,660,546 discloses that the permanent blocking of the canaliculus is performed by utilizing a permanent implant. U.S. Pat. No. 4,660,546 discloses that the permanent implant is fabricated of a non-absorbable or non-dissolvable material and is in the form of a cylindrically shaped central body having a tapered end or an end of reduced diameter to facilitate the implantation of the implant into and for removal of the implant from the canaliculus. Both the temporary collagen implant or other dissolvable material and the permanent implant disclosed in U.S. Pat. No. 4,660,546 are in the form of a cylindrically shaped central member having a predetermined diameter which may terminate at one end in a tapered end and which reduces in diameter as it slopes away from the central member to form a tapered tip to facilitate insertion of the implant through the punctum, and into the canaliculus.
U.S. Pat. No. 4,461,295 discloses another treatment method which is a method for laser punctal occlusion. It is known in the art that punctal occlusion has been proven to be an effective way of treating patients with conditions such as sinusitis, hay fever, middle eye infection (chronic), post nasal drip, front headache and other such conditions.
The treatment method disclosed by U.S. Pat. No. 4,461,295 includes the use of a temporary suture to stitch the tear drainage canals of the eyes closed to determine if a greater tear volume on the surface of the eyes would improve certain eye problems. This diagnostic procedure has become known in the art as the Herrick Stitch Test. The Herrick Stitch Test is performed by anesthetizing the local area around the lower or upper punctum of the eye. A stitch is carefully placed to occlude the punctum by an eye surgeon utilizing magnification of the eye.
After a preselected period of time using the Herrick Stitch Test, the eye surgeon determines if the eye condition has improved, if so, then the eye surgeon permanently closes the punctum by using an ARGON laser. The punctum may be reopened at a later time if excess tearing is experienced. The reopening of the punctum can be performed by surgical and laser techniques, all as disclosed in U.S. Pat. No. 4,461,295.
It is also known in the art to utilize other plugs and or techniques for occluding the punctum. One plug device which is known in the art is referred to as a punctum plug which is described in an article by Jerre M. Freeman, MD, entitled “The Punctum Plug: Evaluation of a New Treatment for the Dry Eye” which appeared in the publication of the transcripts of the America Academy of Ophthalmology and Optometry, pages OP-874 through OP-879 (hereinafter referred to as the “Freeman Reference”). In addition, the same punctum plug is disclosed and described in U.S. Pat. No. 3,949,750.
The punctum plug disclosed in the Freeman Reference and in U.S. Pat. No. 3,949,750 is a plug that is adapted to be inserted into one or more of the upper and/or lower punctal openings of the eye to block or occlude the punctum. The punctum plug of Freeman is a rod-like plug formed with an oversized rigid or solid tip or barb portion that dilates and blockingly projects into the that portion of the canaliculus located adjacent the punctum opening.
The punctum plug has a smaller neck or waist portion around which the punctum sphincter ring or fibrous tissue defining the punctum opening tightens. The punctum plug has relatively large, smooth head portion that rests on top of the punctal opening and is intended to prevent the plug from passing down into the canaliculus. The smooth head portion is designed to be domed shaped to permit the head to rest in the lacrimal lake and against the conjunctiva and cornea, sometimes with irritation. The head portion functions to prevent the punctum plug from passing or migrating further into the canaliculus. The punctum plug of Freeman is subject to being inadvertently removed from the eye by the patient.
It is also known in the art to provide for a temporary closure of the punctum by heat using a light cautery around and in the punctal opening. The punctal closure procedure is disclosed in an article entitled “Diagnosis and Treatment of Keratoconjunctivitis Sicca” which appeared in a symposium on medical and surgical diseases of the cornea, transactions of the New Orleans Academy of Ophthalmology in 1980 at page 43 wherein the authors thereof were Jose I. Barraquer, MD and eight other authors (hereinafter referred to as the “Barraquer Reference”).
The Barraquer Reference further discloses that other treatment methods of temporarily closing the punctum include use of gelatin plugs, cyanoacrylate adhesives and diathermy. The use of intracanalicular gelatin implants for treatment of eye conditions is described in an article entitled “INTRA-CANALICULER GELATIN IMPLANTS IN THE TREATMENT OF KERATO-CONJUNCTIVITIS SICCA” by Wallace S. Foulds which appeared in the Brit J. Ophthal (1961) in Volume 45 at pages 625 through 627, inclusive, (the “Foulds Reference”). The Foulds Reference discloses that occlusion of the lacrimal puncta can be performed by use of and insertion of a fine, water soluble gelatin rod into the punctal openings. The gelatin rod is formed from pure powdered gelatin to which a small quantity of distilled water has been added and is heated in a water bath until the gelatin dissolves and a thick gel results. By dipping a cold glass rod into the so prepared gelatin, and withdrawing the same, fine solid rods of gelatin were formed.
The so formed gelatin rods were then inserted into the canaliculus to provide a temporary blockage. As such, the gelatin rod implants, although very fragile, provide an alternate known means for temporarily blocking the canaliculus. If an improvement in eye condition is obtained, then permanent closure of the canaliculus may be warranted.
It is known in the art that a Schirmer's Tear Secretion Test can be utilized to measure gross tear secretion. If the results of the Schirmer Tear Secretion Test discloses that an insufficient portion of the tear secretion is retained on the eyes, a temporary or permanent occlusion of the canaliculus may prove helpful to improving the above described external eye conditions.
An improvement over the Freeman punctum plug, as described in U.S. Pat. No. 3,949,750, is shown in U.S. Pat. No. 4,915,684. U.S. Pat. No. 4,915,684 discloses a lacrimal fluid-modulating device composed of a generally cylindrical body portion with an enlarged cap at one inlet and a tapered peripheral enlargement at an outlet end. The tapered peripheral enlargement is solid. An axial bore extends completely through the modulating device and is fashioned with an outlet end having an internal diameter that is preferably no less than 0.12 and no greater than 0.36 mm.
A tapered shaft punctum plug for occlusion of the punctum opening having a tapered shaft and including one end that terminates in a narrow neck and a concave dome and another end that terminates in a solid pointed nose is offered for sale by Eagle Vision under the trademark SUPER PLUG.
Another punctum plug that is commercially available for occluding the punctum opening is known as an UMBRELLA PLUG. The UMBRELLA PLUG has an elongated cylindrically shaped central member having one end that is cut at an angle relative to the central axis and terminates in a flat, circular washer like cap or collarette. The UMBRELLA PLUG has at its other end a collapsible umbrella shaped bulb that collapses like the closing of an umbrella during insertion of the umbrella shaped bulb through the punctum and when the umbrella has passed through the punctum opening, it then reverts back to an open position.
U.S. Pat. No. 5,417,651 discloses a punctum plug and probe for lacrimal pathology that includes a plug having a flange, a neck and a foot portion or bulb portion. The flange is inclined at an angle of approximately 130° with respect to the symmetry axis. The foot portion is radially flexible from its resting position towards the symmetry axis. The punctum plug constitutes a head for a metallic mandrel which functions as a probe. The probe follows the path of the lacrimal duct and can be deflected to draw it out of the nasal cavity. The structure of the punctum plug is similar to the UMBRELLA PLUG described above.
U.S. Pat. No. 5,318,513 discloses a fixation stent and a method for using the stent to repair canalicular lacerations and to block fluid flow through a canalicular canal. The stent, adapted to be inserted into a punctum of an eyelid, includes a flexible tube portion having a proximal end, a distal end, an inflatable portion in fluid contact communication with the distal end, and a plug for sealing and anchoring the proximal end with a body canal. The plug includes a T-top portion with a diameter greater than the diameter of he punctum that rests at two specific locations on the margin of the eyelid, thereby anchoring the proximal end of the stent at the margin of the eyelid.
As is evidenced by the above described prior art, the two approaches used to occlude the lacrimal drainage system are to: (a) occlude the punctum opening and that portion of the canaliculus adjacent the punctum opening, e.g., Freeman U.S. Pat. No. 3,949,750, U.S. Pat. No. 4,915,684 the SUPER PUNCTUM PLUG, the UMBRELLA PLUG and the head plug to support a mandrel as shown in U.S. Pat. No. 5,417,651; and (b) occlude the canaliculus at a location other than adjacent the punctum opening, between the punctum opening and lacrimal sac, e.g., U.S. Pat. Nos. 4,660,546 and 5,049,142. However, other implants which can be used to occlude the canaliculus both adjacent the punctum opening and at other locations in the canaliculus and sometimes referred to as canalicular implants, are U.S. Pat. Nos. 5,163,959 and 5,171,270.
The use of a punctum plug as a head for a metallic mandrel which functions as a probe, e.g. U.S. Pat. No. 5,417,651 and for an anchor for a stent to repair canalicular lacerations and to block fluid flow through a canalicular canal, e.g. U.S. Pat. No. 5,318,513, basically are punctum plugs known in the art as described above.
U.S. Pat. No. 4,959,048 discloses a reversible, flexible, lacrimal duct occluder that is formed of a shaft having a low profile cap at one end and a rounded tip at the other end. The shaft has at least one, and preferably 1 through 3, conical ranges forward on the shaft between the ends. The rounded tip enters the punctum followed by the leading edge of the range(s) until the occluder bends at an acute angle relative to the axis of the shaft and enters the horizontal canalicular canal.
In practice, however, it has developed that the transition from that portion of the canaliculus adjacent the punctum opening, sometimes referred to as the vertical portion of this canaliculus, does not occur as a distinct transition point, but rather occurs through an intermediary section referred to as the ampula which anatomically appears to be an extension of that portion of the canaliculus that extends horizontally to the nasal sac.
Therefore, an implant which occludes the punctum opening and that portion of the canaliculus adjacent the punctum opening, depending on its length, can have a portion thereof located in the ampula. By occluding the lacrimal drainage system in this manner, it is not necessary that the implant physically be located in the portion of the canaliculus beyond the ampula to be effective.
On the other hand, if an implant, without a dome or collarette, is inserted into the punctum opening or the portion or section of the canaliculus adjacent the punctum opening, that implant usually migrates through the punctum opening, through the portion of the canaliculus adjacent to the punctum opening, into the ampula, and can easily migrate into that portion of the canaliculus beyond the ampula.
As the use of implants increases to treat the eye, several problems have been encountered. For example, the punctum plug, of which Freeman U.S. Pat. No. 3,949,750, U.S. Pat. No. 4,915,684, the SUPER PUNCTUM PLUG, the UMBRELLA PLUG sometimes migrate completely through the punctum opening and into the canaliculus. In certain instances, implants used to occlude the canaliculus at a location other than adjacent the punctum opening, for example, between the punctum opening and nasal sac sometimes migrate within the canaliculus. In such cases, it is desirable to be able to locate the implant within the canaliculus in order to remove the implant.
In certain patients, an implant inserted into or implanted with the canaliculus can be located and removed by massaging the canaliculus to urge the implant back out of or retrograde through the canaliculus through the punctum opening, which may require mechanical dilation of the punctum. Alternatively, the implant may be urged through the canaliculus to the nasal sac enabling expulsion of the same through the nose.
It is known in the art to use lacrimal irrigation and lacrimal probing of the canaliculus to remove an implant. Another known method for locating and removing an implant involves an invasive procedure, which is undesirable, wherein the canaliculus wall is surgically opened for visually locating the implant, for removing the located implant and then for suturing the canaliculus wall to surgically reclose the wall and adjacent tissue.
Herrick U.S. Pat. No. 5,163,959 discloses at column 13, lines 46 through 59, that a canalicular implant could include material which is responsive to actinic radiation, such as for example, X-rays, so that the eye surgeon can perform tests to determine if the canalicular implant is properly located within the horizontal section of the canaliculus. One such material that can be used is barium, in appropriate concentrations known to persons skilled in the art, so as to be responsive to actinic radiation such as X-rays. The use of such material responsive to actinic radiation is of such low enough level that it does not cause any adverse effects to the patient into which a canalicular implant containing the same is implanted. In such an application, normal X-ray procedures would be used to develop the X-ray image on film to locate the implant.
The problem of locating an implant within the canaliculus is overcome by the teachings of the present invention.